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arXiv 0912.0168cond-mat.str-elcond-mat.other
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共边氧化铜链状化合物NaCu $_{2}$ O $_{2}$的电子结构、磁性和介电性质

Electronic structure, magnetic and dielectric properties of the edge-sharing copper-oxide chain compound NaCu$_{2}$O$_{2}$

Ph. Leininger, M. Rahlenbeck, M. Raichle, B. Bohnenbuck, E. Weschke, E. Schierle, A. Maljuk, C. T. Lin, S. Seki, Y. Tokura, J. W. Freeland, B. Keimer

摘要:

我们报告了一个实验研究的\nco,莫特绝缘体包含链的边缘共享CuO $_4$斑块,通过偏振X射线吸收光谱(XAS),共振磁X射线散射(RMXS),磁化率,和热释电电流测量。的XAS数据表明,价空穴只驻留在铜的氧化物自旋链内的Cu $^{2+}$网站和填充的CuO $_4$斑块内极化的$d$ -轨道。RMXS测量证实了存在的无公度磁序低于$T_N = 11.5$ K的Néel温度,这是以前从中子粉末衍射和核磁共振数据推断。结合磁化率和XAS数据,他们还证明了一个新的“轨道”选择规则RMXS是普遍相关的磁性结构测定通过这种技术。介电性质测量揭示了在$T_N$以下不存在显著的铁电极化,这与对同构化合物\lco的相应观察形成鲜明对比。结果进行了讨论的背景下,目前的多铁性理论。

英文摘要:

We report an experimental study of \nco, a Mott insulator containing chains of edge-sharing CuO$_4$ plaquettes, by polarized x-ray absorption spectroscopy (XAS), resonant magnetic x-ray scattering (RMXS), magnetic susceptibility, and pyroelectric current measurements. The XAS data show that the valence holes reside exclusively on the Cu$^{2+}$ sites within the copper-oxide spin chains and populate a $d$-orbital polarized within the CuO$_4$ plaquettes. The RMXS measurements confirm the presence of incommensurate magnetic order below a Néel temperature of $T_N = 11.5$ K, which was previously inferred from neutron powder diffraction and nuclear magnetic resonance data. In conjunction with the magnetic susceptibility and XAS data, they also demonstrate a new "orbital" selection rule for RMXS that is of general relevance for magnetic structure determinations by this technique. Dielectric property measurements reveal the absence of significant ferroelectric polarization below $T_N$, which is in striking contrast to corresponding observations on the isostructural compound \lco. The results are discussed in the context of current theories of multiferroicity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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